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Licensed Unlicensed Requires Authentication Published by De Gruyter May 23, 2018

TMP properties and refiner conditions in a CD82 chip refiner at different operation points. Part II: Comparison of the five tests

Rita Ferritsius, Olof Ferritsius, Jan Hill, Anders Karlström and Karin Eriksson

Abstract

This paper is part two of a study on a CD 82 TMP chip refiner where relations between changes in the process conditions and changes in the properties of the produced pulp are investigated. Focus is on the ratio between tensile index and specific energy consumption when results from five tests are compared. Pulp properties were measured for composite pulp samples taken from the refiner blow line. Residence times and pulp consistencies were estimated by use of the extended entropy model. Clearly, an increase in specific energy does not necessarily implicate an increase in strength properties of the pulp produced. It is of high importance to have access to information about the refining zone conditions when searching for an optimal operation point in terms of the ratio between tensile index and specific energy. In these tests, this ratio had a maximum at about 55 % measured blow line consistency. Unfavourable operating conditions were identified at high pulp consistencies, especially after the FZ, where pulp consistencies well above 70 % were observed. The estimated residence time for each refining zone responded differently when applying changes in production rate, plate gaps and dilution water flow rates. In conclusion, the results associated with estimated pulp consistencies where easier to interpret compared with results for residence times, implying that additional tests are required for the latter variable. In addition to tensile index, pulp properties like freeness, Somerville shives and light scattering coefficient were included in the analysis.

Funding statement: This publication is part of the Energy Efficient Mechanical Pulping (e2mp) program at Mid Sweden University funded by the Knowledge Foundation, Stora Enso, SCA, Holmen, and Valmet. Special thanks to all who gave support to these trials and testing of the pulps.

  1. Conflict of interest: The authors do not have any conflicts of interest to declare.

Appendix

Table 4

Test 2.

Composite Pulp Sample212223242526272829
Load, MW23.724.624.923.321.923.124.224.221.4
Gap FZ, mm1.351.201.051.211.371.351.361.351.36
Gap CD, mm0.780.790.780.770.770.790.780.750.78
Dil. water FZ, l/s3.423.433.433.433.433.363.263.173.43
Dil. water CD, l/s5.235.245.245.235.235.235.235.245.23
Prod., admt/h15.915.915.915.915.915.915.915.915.9
SE., kWh/admt149315521569147313811457152515271353
Calc. conc. FZ, %76.784.389.877.969.375.981.082.068.2
Calc. conc. CD, %60.064.165.458.953.758.664.065.352.3
Tot. res. time, s1.231.281.301.231.171.221.281.301.15
Res. time ratio FZ/CD1.030.980.971.041.111.051.000.991.13
Force FZ 3, N1.111.201.261.191.211.151.111.131.26
Pulp conc., %57.661.062.657.053.558.962.564.253.8
Freeness, ml CSF198192182197225202192193230
Fiber length (ww), mm2.111.961.922.152.292.202.032.012.31
CWT, μm7.88.07.87.97.88.07.97.98.0
Fibrillation, %5.435.645.625.395.565.826.065.675.62
Curl, %14.113.613.513.613.613.913.813.413.6
Somerville, %1.611.151.041.461.781.441.321.341.79
Density, kg/m3329352362343330343348358326
Tensile index, Nm/g27.727.228.030.129.729.627.327.129.1
Elongation, %1.781.711.731.821.731.791.781.731.83
Tear index, mNm2/g6.375.725.866.727.216.885.956.117.27
Light scatt. coeff. m2/kg45.347.748.145.943.245.547.047.843.5

Table 5

Test 3.

Composite Pulp Sample31323334
Load, MW22.422.122.121.9
Gap FZ, mm1.231.241.221.23
Gap CD, mm0.630.570.630.64
Dil. water FZ, l/s3.783.793.783.79
Dil. water CD, l/s5.125.115.125.06
Prod., admt/h15.015.015.015.0
SE., kWh/admt1496147614701463
Calc. conc. FZ, %60.758.059.859.5
Calc. conc. CD, %50.649.649.449.5
Tot. res. time, s1.031.151.151.15
Res. time ratio FZ/CD1.130.990.990.99
Force FZ 3, N1.231.281.271.25
Pulp conc., %51.451.450.850.8
Freeness, ml CSF214212213220
Fiber length (ww), mm2.222.212.282.20
CWT, μm7.97.97.87.9
Fibrillation, %5.485.315.725.72
Curl, %14.513.714.814.0
Somerville, %1.781.881.751.86
Density, kg/m3316328337340
Tensile index, Nm/g26.826.327.827.9
Elongation, %1.781.711.771.78
Tear index, mNm2/g6.426.366.826.79
Light scatt. coeff. m2/kg44.044.243.843.9

Table 6

Test 4.

Composite Pulp Sample353637383940414243444546474849
Load, MW19.719.619.719.519.621.521.521.621.321.322.522.522.322.422.5
Gap FZ, mm1.481.481.481.491.481.481.471.471.481.481.491.481.481.481.48
Gap CD, mm1.141.141.131.131.141.151.151.151.151.141.111.121.141.141.13
Dil. water FZ, l/s3.393.393.393.393.403.413.403.403.393.393.383.413.403.433.38
Dil. water CD, l/s3.893.883.883.883.883.883.883.883.883.893.883.893.883.893.88
Prod., admt/h12.512.512.512.512.514.414.414.414.414.415.915.915.915.915.9
SE., kWh/admt158015661578156415681490149414971478148214181415140314101418
Calc. conc. FZ, %75.575.075.074.174.276.076.476.575.275.676.676.275.875.677.6
Calc. conc. CD, %-58.658.657.657.764.564.965.263.964.265.965.465.065.366.1
Tot. res. time, s1.591.581.581.571.571.471.481.481.461.471.361.351.351.351.36
Res. time ratio FZ/CD0.850.850.850.860.860.800.800.800.810.810.800.800.800.800.80
Force FZ 3, N0.560.550.560.580.580.790.780.800.780.790.991.021.000.990.99
Pulp conc., %56.763.260.358.958.867.768.570.464.065.870.873.270.969.575.8
Freeness, ml CSF183198190191194235235260226253303327295280307
Fiber length (ww), mm2.342.332.322.332.322.312.312.282.302.312.332.342.342.362.28
CWT, μm7.67.77.87.77.77.97.98.07.97.98.18.28.08.08.3
Fibrillation, %6.76.476.426.386.66.136.246.186.096.196.156.126.286.155.97
Curl, %15.315.115.114.915.414.414.614.514.614.614.614.615.014.814.2
Somerville, %0.880.920.850.780.951.261.271.221.321.281.401.541.431.391.34
Density, kg/m3362355360360364341352350356346336337339350339
Tensile index, Nm/g34.431.633.132.932.928.128.628.030.528.425.524.527.228.124.9
Elongation, %1.921.831.861.911.881.751.661.671.711.691.531.561.631.681.56
Tear index, mNm2/g7.477.227.597.317.377.166.956.486.936.616.196.236.556.836.06
Light scatt. coeff. m2/kg47.547.447.347.147.346.047.147.447.346.445.244.645.245.444.9

Table 7

Test 5.

Composite Pulp Sample505152535455565758596061626364
Load, MW21.922.322.122.122.618.418.118.518.918.720.019.018.817.617.4
Gap FZ, mm0.870.870.860.860.870.850.850.860.860.860.850.860.850.850.86
Gap CD, mm0.670.670.670.670.650.650.640.650.650.650.670.660.660.650.65
Dil. water FZ, l/s3.293.283.283.283.283.513.513.513.513.513.513.513.513.513.52
Dil. water CD, l/s4.694.704.704.694.704.694.694.694.694.694.454.444.454.444.44
Prod., admt/h14.214.214.214.214.214.314.314.314.314.314.214.214.214.214.2
SE., kWh/admt154015681555155515881285126412971321130614071339132212431223
Calc. conc. FZ, %61.262.562.162.262.553.452.953.654.353.956.454.654.252.451.9
Calc. conc. CD, %57.759.258.458.560.445.444.745.746.846.251.548.848.145.244.5
Tot. res. time, s1.161.171.171.171.181.041.031.041.051.051.101.071.061.041.03
Res. time ratio FZ/CD0.940.920.930.930.901.111.131.111.091.101.011.051.061.111.12
Force FZ 3, N1.561.641.621.631.681.281.271.301.321.311.421.291.301.251.26
Pulp conc., %59.061.259.660.761.445.043.745.548.048.649.049.748.744.344.4
Freeness, ml CSF190194194203205262270259252253214235244286295
Fiber length (ww), mm2.292.242.222.242.192.332.392.392.342.372.342.382.352.332.38
CWT, μm7.87.87.97.88.07.87.87.87.87.97.97.87.77.67.7
Fibrillation, %6.36.36.46.296.25.926.036.056.036.126.166.056.045.916.12
Curl, %14.714.514.514.914.413.714.013.614.013.914.213.914.113.813.9
Somerville, %0.860.760.750.800.641.752.001.661.751.721.321.421.752.242.28
Density, kg/m3372375376381373333329340340338348333329331327
Tensile index, Nm/g34.233.833.933.532.127.926.828.529.128.831.229.027.226.025.8
Elongation, %1.801.831.811.911.821.761.711.761.811.761.851.781.781.681.75
Tear index, mNm2/g7.447.517.747.547.127.186.887.167.147.107.357.266.926.756.44
Light scatt. coeff. m2/kg46.647.247.146.547.143.243.042.843.443.544.543.543.142.041.9

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Received: 2016-09-21
Accepted: 2017-12-12
Published Online: 2018-05-23
Published in Print: 2018-05-23

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